i for one is discomfort with a person who is or does complain about his job.
The usual rants
A complain comes only if the person does not know how to deliver the job,

A complain comes only if a person does want to investigate what happen to prior to complaining about the issue.

A complain comes when he is given a task, even worse if he doesnt know how to deliver the task!

Let me share with you this,

1. you are a employee, your boss gives u a task, why does he give you?
because you are paid to do so. right? why complain?

2. why he doesnt gives it to another person? because he knows you are good with your work or u have time to spare (positive/negative its your choice)

Now if you are indeed very tight down with work, talk to your boss about it, let him know that you are tight down with your load, ask him for more time, if he insists that you to take it. Negotiate with him. give him a solution instead ask for an answer, tell him you need X amount of time to finish your work nicely n live to it. Now if he does not gives u ample time to finish your load, Spend more time working, because at the end of the day your CV will be much nicer. and its time for an employer who pays you more because of your more beautiful CV. Therefore it pays to work hard .